Probabilistic Seismic Hazard Analysis and Site Characterization of a Powerplant Site in Chittagong, Bangladesh

Abstract

In the present study, the Probabilistic Seismic Hazard Analysis (PSHA) has been carried out for a powerplant site in Chittagong using the latest available information on seismicity in the region. The latest updated earthquake catalog homogenized in uniform moment magnitude scale was prepared. Seismicity analysis was carried out, and the seismicity parameters for the region were estimated from the frequency magnitude distribution plot. The peak ground acceleration (PGA) and the spectral acceleration at the bedrock for 10% and 2% probability of exceedance within 50 years were evaluated using different source models and attenuation relations in a logic tree framework. The site was characterized based on the soil investigation data from 31 boreholes and amplification factors considering the local geology (SPT-N values) were obtained through ground response analysis. Subsequently, the surface level peak ground acceleration was estimated and depicted in the form of hazard contour maps.